Sensitivity study of a suspension bridge

Pao Yue-kong Library Electronic Theses Database

Sensitivity study of a suspension bridge

 

Author: Cheung, Wendy Y. Y
Title: Sensitivity study of a suspension bridge
Degree: M.Sc.
Year: 1996
Subject: Suspension bridges -- China -- Hong Kong -- Testing
Computer simulation
Hong Kong Polytechnic University -- Dissertations
Department: Multi-disciplinary Studies
Pages: v, 127, [107] leaves : ill. ; 30 cm
Language: English
InnoPac Record: http://library.polyu.edu.hk/record=b1239021
URI: http://theses.lib.polyu.edu.hk/handle/200/4761
Abstract: In Hong Kong, many advanced technical skills in the construction industry had been established and can be seen from the rapid developments over the past years. However, the design and construction of cable-supported bridges are still fresh and green to the Construction Industry of Hong Kong in comparison with other countries in America and Europe. It is essential for a bridge to be well maintained at all times throughout its design life. In order to achieve this, structural health monitoring is required to be undertaken at regular intervals for stability control and damage assessment of the bridge. The structural health monitoring of the bridge can be accomplished by carrying out sensitivity study of a model bridge to investigate the system dynamic characteristics in terms of mode shapes and frequencies and to study the sensitivity to the change of system parameters, such as Young's Modulus, Area. A computer model is established for carrying out sensitivity studies on various system parameters using the Tsing Ma Bridge as an example and it is found that the Young's Modulus of the bridge deck has the largest effect on the natural frequencies and mode shapes of the system. However, the effects vary with different modes. Damage detection study is done by modelling the fictitious damages and defects such as: a) rusting of cables and hangers causing reduction in cross-sectional areas, and b) disconnection of hangers in various sections of the bridge to study the variation in dynamic behaviour. It is found that local rusting of cables and hangers will not affect the dynamic characteristics of the bridge significantly. However, disconnection of a hanger will give arise to change in natural frequencies of the bridge and the magnitudes and mode shapes affected will depend on the location of the damage occurred. Sensitivity of the dynamic characteristic on a number of system parameters are also carried out using a self-developed program. Skyline storage of the stiffness and mass matrices of the system is used to reduce the storage required for the performance of Subspace Iteration to obtain eigenvalues (frequencies) and eigenvectors (mode shapes) of the system. System parameters including Young's Modulus, cross-sectional area and shear area are considered in the sensitivity study. However, due to the limitation of time and perhaps the insufficient memory available in the computer, the program can only be partially developed.

Files in this item

Files Size Format
b12390215.pdf 6.364Mb PDF
Copyright Undertaking
As a bona fide Library user, I declare that:
  1. I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
  2. I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
  3. I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.

     

Quick Search

Browse

More Information